Individual differences in children's strategy selection in a computational estimation task with two versus three available strategies.

We investigated how children's strategy selection on different problem types was influenced by whether two or three strategies were available in a computational estimation task. Importantly, we examined the influence of individual differences in working memory updating on these effects. Third and fourth graders (N = 725) were asked to indicate the best strategy for two-digit addition problems (e.g., 47 + 24) without calculating estimates. Homogeneous problems (i.e., both unit digits smaller than 5 or larger than 5) and heterogeneous problems (i.e., one operand's unit digit smaller than 5 and the other's unit digit larger than 5) were included. Children completed selection tasks under two conditions: (a) a three-strategy condition, in which they could choose among the rounding-down strategy (i.e., rounding both operands down), the mixed-rounding strategy (i.e., rounding one operand down and the other operand up), and the rounding-up strategy (i.e., rounding both operands up), and (b) a two-strategy condition, in which they could select between the rounding-down strategy and the rounding-up strategy only. As expected, children chose the best available strategy more often under the three-strategy condition than under the two-strategy condition and more often on homogeneous problems than on heterogeneous problems. Importantly, these effects were moderated by children's updating capacities. That is, children with less efficient updating showed worse selection performance on heterogeneous problems than on homogeneous problems under both conditions. In turn, children with more efficient updating showed comparable performance for both problem types under both conditions. These findings have important implications to further our understanding of underlying processes in children's strategy selection in computational estimation.

Effects of working memory updating on children's arithmetic performance and strategy use: A study in computational estimation.

The current study investigated how children's working memory updating processes influence arithmetic performance and strategy use. Large samples of third and fourth graders were asked to find estimates of two-digit addition problems (e.g., 42 + 76). On each problem, children could choose between the rounding-down strategy (i.e., rounding both operands down to the closest decades) or the rounding-up strategy (i.e., rounding both operands up to the closest decades). Four tasks were used to assess updating. Analyses of strategy use revealed that children with more efficient updating showed higher levels of (a) strategy flexibility (i.e., they were less likely to use a single strategy on all or nearly all problems within a test block), (b) strategy adaptivity (i.e., they selected the better strategy overall more often and were more adaptive specifically on homogeneous and rounding-up problems), and (c) strategy performance (i.e., they tended to execute strategies more quickly, especially on homogeneous and larger problems). Finally, updating exerted a more important role for problem type effects in younger children than in older children. These findings have important implications for further understanding how working memory updating processes influence children's arithmetic performance and age-related differences therein.

Effects of presentation modality and duration on children's strategy use: A study in computational estimation.

Two experiments were run to determine how presentation modality and duration influence children's arithmetic performance and strategy selection. Third and fourth graders were asked to find estimates for two-digit addition problems (e.g., 52 + 39). Children were tested in three conditions: (1) time-unlimited visual, (2) time-limited visual, or (3) time-limited auditory conditions. Moreover, we assessed children's working-memory updating and arithmetic fluency. Children were told which strategy to use on each problem to assess arithmetic performance while executing strategies, in Experiment 1, and were asked to choose the best strategy of three available strategies to assess strategy selection, in Experiment 2. Presentation modality influenced strategy execution (i.e., children were faster and more accurate in problems under visual than auditory conditions) but only in children with low updating abilities. In contrast, presentation modality had no effect on children's strategy selection. Presentation duration had an effect on both strategy execution and strategy selection with time-limited presentation leading to a decline in children's performance. Interestingly, specifically in children with low updating abilities, time-limited presentation led to poorer performance. Hence, efficient updating seemed to compensate for detrimental effects of auditory in comparison to visual and time-limited in comparison to time-unlimited presentation. These findings have important implications for determining conditions under which children execute strategies most efficiently and select the best strategy on each problem most often, as well as for understanding mechanisms underlying strategic behaviour.

Effects of COVID-19-Related School Closures on Student Achievement-A Systematic Review.

The COVID-19 pandemic led to numerous governments deciding to close schools for several weeks in spring 2020. Empirical evidence on the impact of COVID-19-related school closures on academic achievement is only just emerging. The present work aimed to provide a first systematic overview of evidence-based studies on general and differential effects of COVID-19-related school closures in spring 2020 on student achievement in primary and secondary education. Results indicate a negative effect of school closures on student achievement, specifically in younger students and students from families with low socioeconomic status. Moreover, certain measures can be identified that might mitigate these negative effects. The findings are discussed in the context of their possible consequences for national educational policies when facing future school closures.